108 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



breast-height measurement are known. The estimator recognises 

 that by measuring a number of blown or felled trees in the area 

 he can establish a relationship between the measured breast- 

 height value and the value of any section at any point in the 

 stem of the tree. The relationship can be established equally 

 well for measurements of quarter-girth, diameter, or of girth. 

 When, then, the average trees on which the estimate is to be 

 based are standing trees, provided the taper or decrease of 

 measurement per known length of stem has been obtained, 

 and the values of timber-length have been determined, it is 

 possible to reckon value of sectional area at half the timber- 

 height. The volume can be reckoned then in usual manner. 

 The procedure involves reckoning even in areas where taper 

 is known. 



Tables can be arranged to indicate directly the volume of 

 any tree of known timber-length with certain breast-height 

 measurement and with definite taper. These tables could be 

 arranged for all gradations of taper, but it is possible that 

 it would be found sufficient to have tables arranged for decrease 

 in diameter of I, h, i, i|, and i| inches per 10 feet of "run" 

 on tree. The idea is not new, and as it exists it may be 

 of interest to attempt to develop it. Reliable form factors may 

 require a long series of observations ; it is equally true that 

 a similar series would be necessary for taper estimates over 

 wide areas. The taper in any one case can, however, be 

 easily found, and the use of such tables then merely amounts 

 to using a type of ready reckoner. It is obvious that the 

 tables can be equally well used for all species. These tables 

 could be used in any case where the timber-length was 

 determined, and the size fixed as timber limit would not 

 affect them. 



In the specimen table that follows, volume is stated for 

 trees of any breast-height diameter and of varying length when 

 the trees show a decrease in diameter of i inch in a "run" 

 of 10 feet. Breast-height has been taken as 4 feet from ground 

 in order to facilitate reckonings. Table given is a skeleton one 

 to show method only. It would be interesting to have remarks 

 of readers. 



Mr J. Rennie was kind enough to check my figures for the 

 skeleton table given on next page. 



J. F. 



